Semiconductor image sensors are sued for sensing light. Complementary metal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors can be seen in various applications such as digital still camera or mobile phone camera. These devices employ an array of pixels in a substrate, including photodiodes and transistors, that can absorb radiation projected toward the substrate and convert the sensed radiation into electrical signals.
A back-side illuminated (BSI) image sensor device is one type of image sensor device. As transistor size shrinks with the advance of manufacturing technique, existing BSI image sensor may suffer from issues related to cross-talk and blooming. These issues may be caused by insufficient isolation between neighbouring pixels of the BSI image sensor.
Therefore, while concurrent method of fabricating BSI image sensor devices have been generally adequate for their intended purpose, they have not been entirely satisfactory in every aspect.